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1.
EMBO Mol Med ; 16(4): 723-754, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38514791

RESUMO

Vaccination with infectious Plasmodium falciparum (Pf) sporozoites (SPZ) administered with antimalarial drugs (PfSPZ-CVac), confers superior sterilizing protection against infection when compared to vaccination with replication-deficient, radiation-attenuated PfSPZ. However, the requirement for drug administration constitutes a major limitation for PfSPZ-CVac. To obviate this limitation, we generated late liver stage-arresting replication competent (LARC) parasites by deletion of the Mei2 and LINUP genes (mei2-/linup- or LARC2). We show that Plasmodium yoelii (Py) LARC2 sporozoites did not cause breakthrough blood stage infections and engendered durable sterilizing immunity against various infectious sporozoite challenges in diverse strains of mice. We next genetically engineered a PfLARC2 parasite strain that was devoid of extraneous DNA and produced cryopreserved PfSPZ-LARC2. PfSPZ-LARC2 liver stages replicated robustly in liver-humanized mice but displayed severe defects in late liver stage differentiation and did not form liver stage merozoites. This resulted in complete abrogation of parasite transition to viable blood stage infection. Therefore, PfSPZ-LARC2 is the next-generation vaccine strain expected to unite the safety profile of radiation-attenuated PfSPZ with the superior protective efficacy of PfSPZ-CVac.


Assuntos
Vacinas Antimaláricas , Malária Falciparum , Parasitos , Animais , Camundongos , Plasmodium falciparum/genética , Malária Falciparum/prevenção & controle , Deleção de Genes , Vacinas Antimaláricas/genética , Vacinas Atenuadas/genética , Esporozoítos/genética
2.
Sci Rep ; 14(1): 2881, 2024 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-38311678

RESUMO

Radiation-attenuated sporozoite (RAS) vaccines can completely prevent blood stage Plasmodium infection by inducing liver-resident memory CD8+ T cells to target parasites in the liver. Such T cells can be induced by 'Prime-and-trap' vaccination, which here combines DNA priming against the P. yoelii circumsporozoite protein (CSP) with a subsequent intravenous (IV) dose of liver-homing RAS to "trap" the activated and expanding T cells in the liver. Prime-and-trap confers durable protection in mice, and efforts are underway to translate this vaccine strategy to the clinic. However, it is unclear whether the RAS trapping dose must be strictly administered by the IV route. Here we show that intradermal (ID) RAS administration can be as effective as IV administration if RAS are co-administrated with the glycolipid adjuvant 7DW8-5 in an ultra-low inoculation volume. In mice, the co-administration of RAS and 7DW8-5 in ultra-low ID volumes (2.5 µL) was completely protective and dose sparing compared to standard volumes (10-50 µL) and induced protective levels of CSP-specific CD8+ T cells in the liver. Our finding that adjuvants and ultra-low volumes are required for ID RAS efficacy may explain why prior reports about higher volumes of unadjuvanted ID RAS proved less effective than IV RAS. The ID route may offer significant translational advantages over the IV route and could improve sporozoite vaccine development.


Assuntos
Vacinas Antimaláricas , Malária , Camundongos , Animais , Esporozoítos , Linfócitos T CD8-Positivos , Glicolipídeos , Malária/parasitologia , Adjuvantes Imunológicos/farmacologia , Adjuvantes Farmacêuticos , Camundongos Endogâmicos BALB C
3.
Nat Biomed Eng ; 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38082180

RESUMO

Lipid nanoparticles (LNPs) can be designed to potentiate cancer immunotherapy by promoting their uptake by antigen-presenting cells, stimulating the maturation of these cells and modulating the activity of adjuvants. Here we report an LNP-screening method for the optimization of the type of helper lipid and of lipid-component ratios to enhance the delivery of tumour-antigen-encoding mRNA to dendritic cells and their immune-activation profile towards enhanced antitumour activity. The method involves screening for LNPs that enhance the maturation of bone-marrow-derived dendritic cells and antigen presentation in vitro, followed by assessing immune activation and tumour-growth suppression in a mouse model of melanoma after subcutaneous or intramuscular delivery of the LNPs. We found that the most potent antitumour activity, especially when combined with immune checkpoint inhibitors, resulted from a coordinated attack by T cells and NK cells, triggered by LNPs that elicited strong immune activity in both type-1 and type-2 T helper cells. Our findings highlight the importance of optimizing the LNP composition of mRNA-based cancer vaccines to tailor antigen-specific immune-activation profiles.

4.
Res Sq ; 2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37609210

RESUMO

Malaria is caused by Plasmodium parasites and was responsible for over 247 million infections and 619,000 deaths in 2021. Radiation-attenuated sporozoite (RAS) vaccines can completely prevent blood stage infection by inducing protective liver-resident memory CD8+ T cells. Such T cells can be induced by 'prime-and-trap' vaccination, which here combines DNA priming against the P. yoelii circumsporozoite protein (CSP) with a subsequent intravenous (IV) dose of liver-homing RAS to "trap" the activated and expanding T cells in the liver. Prime-and-trap confers durable protection in mice, and efforts are underway to translate this vaccine strategy to the clinic. However, it is unclear whether the RAS trapping dose must be strictly administered by the IV route. Here we show that intradermal (ID) RAS administration can be as effective as IV administration if RAS are co-administrated with the glycolipid adjuvant 7DW8-5 in an ultra-low inoculation volume. In mice, the co-administration of RAS and 7DW8-5 in ultra-low ID volumes (2.5 µL) was completely protective and dose sparing compared to standard volumes (10-50 µL) and induced protective levels of CSP-specific CD8+ T cells in the liver. Our finding that adjuvants and ultra-low volumes are required for ID RAS efficacy may explain why prior reports about higher volumes of unadjuvanted ID RAS proved less effective. The ID route may offer significant translational advantages over the IV route and could improve sporozoite vaccine development.

5.
Expert Rev Vaccines ; 22(1): 964-1007, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37571809

RESUMO

INTRODUCTION: Malaria, a devastating febrile illness caused by protozoan parasites, sickened 247,000,000 people in 2021 and killed 619,000, mostly children and pregnant women in sub-Saharan Africa. A highly effective vaccine is urgently needed, especially for Plasmodium falciparum (Pf), the deadliest human malaria parasite. AREAS COVERED: Sporozoites (SPZ), the parasite stage transmitted by Anopheles mosquitoes to humans, are the only vaccine immunogen achieving >90% efficacy against Pf infection. This review describes >30 clinical trials of PfSPZ vaccines in the U.S.A., Europe, Africa, and Asia, based on first-hand knowledge of the trials and PubMed searches of 'sporozoites,' 'malaria,' and 'vaccines.' EXPERT OPINION: First generation (radiation-attenuated) PfSPZ vaccines are safe, well tolerated, 80-100% efficacious against homologous controlled human malaria infection (CHMI) and provide 18-19 months protection without boosting in Africa. Second generation chemo-attenuated PfSPZ are more potent, 100% efficacious against stringent heterologous (variant strain) CHMI, but require a co-administered drug, raising safety concerns. Third generation, late liver stage-arresting, replication competent (LARC), genetically-attenuated PfSPZ are expected to be both safe and highly efficacious. Overall, PfSPZ vaccines meet safety, tolerability, and efficacy requirements for protecting pregnant women and travelers exposed to Pf in Africa, with licensure for these populations possible within 5 years. Protecting children and mass vaccination programs to block transmission and eliminate malaria are long-term objectives.


Assuntos
Vacinas Antimaláricas , Malária Falciparum , Malária , Gravidez , Criança , Animais , Humanos , Feminino , Esporozoítos , Ciência Translacional Biomédica , Vacinas Atenuadas , Malária/prevenção & controle , Malária Falciparum/prevenção & controle , Plasmodium falciparum , Imunização
6.
PLoS One ; 16(9): e0257145, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34492078

RESUMO

Plastic surgery is growing in popularity. Despite this, there has been little exploration to date regarding the psychosocial consequences of seeking plastic surgery. Our study investigated how women seeking plastic surgery are perceived by others. We presented a random sample of 985 adults (men = 54%, Mage = 35.84 years, SDage = 10.59) recruited via Amazon's Mechanical Turk with a series of experimental stimuli consisting of a photographed woman (attractive versus unattractive) and a vignette describing an activity she plans to engage in (plastic surgery versus control activity). Participants rated stimuli on perceived warmth, competence, morality, and humanness. We ran linear mixed-effect models to assess all study hypotheses. There was a negative plastic surgery effect; that is, women seeking plastic surgery were perceived less favorably than those planning to complete control activities across all outcome variables (warmth, competence, morality, and humanness). These relationships were moderated by physical attractiveness; while attractive women planning to undergo plastic surgery were perceived less favorably than attractive women planning to engage in control activities, perceptions of unattractive individuals remained unchanged by plastic surgery status. We theorized that empathy toward unattractive women seeking plastic surgery mitigated the negative plastic surgery effect for these women. In sum, our results suggest that perceptions of attractive women are worsened when these women decide to seek cosmetic surgery. Perceptions of warmth and competence have implications for an individual's self-esteem and interpersonal relationships, while perceptions of morality and humanness can impact an individual's ability to fulfil their psychological needs. As such, we concluded that attractive women seeking plastic surgery are potentially subject to experience negative psychosocial outcomes. Future research ought to examine whether perceptions and outcomes differ for women seeking reconstructive plastic surgery (versus cosmetic plastic surgery) and whether they differ across different types of surgeries (i.e. face versus body).


Assuntos
Percepção , Cirurgia Plástica/psicologia , Adulto , Beleza , Feminino , Humanos , Masculino
7.
PLoS One ; 16(9): e0257560, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34543346

RESUMO

Certain clinical indications and treatments such as the use of rasburicase in cancer therapy and 8-aminoquinolines for Plasmodium vivax malaria treatment would benefit from a point-of-care test for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Three studies were conducted to evaluate the performance of one such test: the STANDARD™ G6PD Test (SD BIOSENSOR, South Korea). First, biological interference on the test performance was evaluated in specimens with common blood disorders, including high white blood cell (WBC) counts. Second, the test precision on fingerstick specimens was evaluated against five individuals of each, deficient, intermediate, and normal G6PD activity status. Third, clinical performance of the test was evaluated at three point-of-care settings in the United States. The test performed equivalently to the reference assay in specimens with common blood disorders. High WBC count blood samples resulted in overestimation of G6PD activity in both the reference assay and the STANDARD G6PD Test. The STANDARD G6PD Test showed good precision on multiple fingerstick specimens from the same individual. The same G6PD threshold values (U/g Hb) were applied for a semiquantitative interpretation for fingerstick- and venous-derived results. The sensitivity/specificity values (95% confidence intervals) for the test for G6PD deficiency were 100 (92.3-100.0)/97 (95.2-98.2) and 100 (95.7-100.0)/97.4 (95.7-98.5) for venous and capillary specimens, respectively. The same values for females with intermediate (> 30% to ≤ 70%) G6PD activity were 94.1 (71.3-99.9)/88.2 (83.9-91.7) and 82.4 (56.6-96.2)/87.6(83.3-91.2) for venous and capillary specimens, respectively. The STANDARD G6PD Test enables point-of-care testing for G6PD deficiency.


Assuntos
Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Glucosefosfato Desidrogenase/sangue , Sistemas Automatizados de Assistência Junto ao Leito/normas , Adolescente , Adulto , Idoso , Coleta de Amostras Sanguíneas , Criança , Pré-Escolar , Feminino , Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/normas , Deficiência de Glucosefosfato Desidrogenase/complicações , Doenças Hematológicas/complicações , Hemoglobinas/análise , Humanos , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Kit de Reagentes para Diagnóstico , Padrões de Referência , Sensibilidade e Especificidade , Adulto Jovem
8.
JCI Insight ; 5(13)2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32484795

RESUMO

Whole-sporozoite vaccines engender sterilizing immunity against malaria in animal models and importantly, in humans. Gene editing allows for the removal of specific parasite genes, enabling generation of genetically attenuated parasite (GAP) strains for vaccination. Using rodent malaria parasites, we have previously shown that late liver stage-arresting replication-competent (LARC) GAPs confer superior protection when compared with early liver stage-arresting replication-deficient GAPs and radiation-attenuated sporozoites. However, generating a LARC GAP in the human malaria parasite Plasmodium falciparum (P. falciparum) has been challenging. Here, we report the generation and characterization of a likely unprecedented P. falciparum LARC GAP generated by targeted gene deletion of the Mei2 gene: P. falciparum mei2-. Robust exoerythrocytic schizogony with extensive cell growth and DNA replication was observed for P. falciparum mei2- liver stages in human liver-chimeric mice. However, P. falciparum mei2- liver stages failed to complete development and did not form infectious exoerythrocytic merozoites, thereby preventing their transition to asexual blood stage infection. Therefore, P. falciparum mei2- is a replication-competent, attenuated human malaria parasite strain with potentially increased potency, useful for vaccination to protect against P. falciparum malaria infection.


Assuntos
Vacinas Antimaláricas/farmacologia , Malária Falciparum/prevenção & controle , Malária/prevenção & controle , Parasitos/efeitos dos fármacos , Esporozoítos/patogenicidade , Animais , Humanos , Fígado/imunologia , Malária/parasitologia , Malária Falciparum/tratamento farmacológico , Parasitos/imunologia , Parasitos/patogenicidade , Plasmodium falciparum/genética , Plasmodium yoelii/imunologia , Vacinação/métodos , Vacinas Atenuadas/imunologia
9.
Clin Infect Dis ; 71(6): 1481-1490, 2020 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-31621832

RESUMO

BACKGROUND: Chemoprophylaxis vaccination with sporozoites (CVac) with chloroquine induces protection against a homologous Plasmodium falciparum sporozoite (PfSPZ) challenge, but whether blood-stage parasite exposure is required for protection remains unclear. Chloroquine suppresses and clears blood-stage parasitemia, while other antimalarial drugs, such as primaquine, act against liver-stage parasites. Here, we evaluated CVac regimens using primaquine and/or chloroquine as the partner drug to discern whether blood-stage parasite exposure impacts protection against homologous controlled human malaria infection. METHODS: In a Phase I, randomized, partial double-blind, placebo-controlled study of 36 malaria-naive adults, all CVac subjects received chloroquine prophylaxis and bites from 12-15 P. falciparum-infected mosquitoes (CVac-chloroquine arm) at 3 monthly iterations, and some received postexposure primaquine (CVac-primaquine/chloroquine arm). Drug control subjects received primaquine, chloroquine, and uninfected mosquito bites. After a chloroquine washout, subjects, including treatment-naive infectivity controls, underwent homologous, PfSPZ controlled human malaria infection and were monitored for parasitemia for 21 days. RESULTS: No serious adverse events occurred. During CVac, all but 1 subject in the study remained blood-smear negative, while only 1 subject (primaquine/chloroquine arm) remained polymerase chain reaction-negative. Upon challenge, compared to infectivity controls, 3/3 chloroquine arm subjects displayed delayed patent parasitemia (P = .01) but not sterile protection, while 3/11 primaquine/chloroquine subjects remained blood-smear negative. CONCLUSIONS: CVac-primaquine/chloroquine is safe and induces sterile immunity to P. falciparum in some recipients, but a single 45 mg dose of primaquine postexposure does not completely prevent blood-stage parasitemia. Unlike previous studies, CVac-chloroquine did not produce sterile immunity. CLINICAL TRIALS REGISTRATION: NCT01500980.


Assuntos
Antimaláricos , Malária Falciparum , Adulto , Animais , Antimaláricos/uso terapêutico , Quimioprevenção , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/prevenção & controle , Plasmodium falciparum , Esporozoítos , Vacinação
10.
Malar J ; 17(1): 23, 2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-29321025

RESUMO

BACKGROUND: Autosplenectomy, as a result of sickle cell disease, is an important risk factor for severe malaria. While molecular methods are helpful in providing rapid and accurate infection detection and species identification, the effect of hyposplenism on result interpretation during the course of infection should be carefully considered. CASE PRESENTATION: A 32-year old autosplenectomized Nigerian male with severe sickle cell disease was referred to the National Institutes of Health for allogenic hematopoietic stem cell transplant. Despite testing negative for malaria by both smear and PCR 2 weeks after arrival in the USA, the patient developed fever and diffuse bilateral lower rib cage and upper abdominal pain 2 weeks later and subsequently tested positive for Plasmodium falciparum. Parasitaemia was tracked over time by microscopy and nucleic acid tests to evaluate the therapeutic response in the setting of hyposplenism. The patient showed prompt resolution of patent infection by microscopy but remained positive by molecular methods for > 30 days after treatment initiation. CONCLUSION: While molecular testing can provide sensitive Plasmodium nucleic acid detection, the persistence of Plasmodium nucleic acids following adequate treatment in functionally asplenic patients can lead to a diagnostic dilemma. In such patients, clinical response and peripheral blood smears should guide patient management following treatment. Nonetheless, in pre-transplant patients at high-risk for pre-existing Plasmodium infections, highly sensitive molecular assays can be useful to rule out infection prior to transplantation.


Assuntos
Anemia Falciforme/complicações , Antimaláricos/uso terapêutico , DNA de Protozoário/sangue , Monitoramento de Medicamentos/métodos , Malária Falciparum/diagnóstico , Malária Falciparum/patologia , Adulto , Humanos , Malária Falciparum/tratamento farmacológico , Masculino , Microscopia , Ácidos Nucleicos , Reação em Cadeia da Polimerase , Fatores de Tempo , Estados Unidos
11.
J Infect Dis ; 217(5): 693-702, 2018 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-29216395

RESUMO

Background: DSM265 is a selective inhibitor of Plasmodium dihydroorotate dehydrogenase that fully protected against controlled human malarial infection (CHMI) by direct venous inoculation of Plasmodium falciparum sporozoites when administered 1 day before challenge and provided partial protection when administered 7 days before challenge. Methods: A double-blinded, randomized, placebo-controlled trial was performed to assess safety, tolerability, pharmacokinetics, and efficacy of 1 oral dose of 400 mg of DSM265 before CHMI. Three cohorts were studied, with DSM265 administered 3 or 7 days before direct venous inoculation of sporozoites or 7 days before 5 bites from infected mosquitoes. Results: DSM265-related adverse events consisted of mild-to-moderate headache and gastrointestinal symptoms. DSM265 concentrations were consistent with pharmacokinetic models (mean area under the curve extrapolated to infinity, 1707 µg*h/mL). Placebo-treated participants became positive by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and were treated 7-10 days after CHMI. Among DSM265-treated subjects, 2 of 6 in each cohort were sterilely protected. DSM265-treated recipients had longer times to development of parasitemia than placebo-treated participants (P < .004). Conclusions: This was the first CHMI study of a novel antimalarial compound to compare direct venous inoculation of sporozoites and mosquito bites. Times to qRT-PCR positivity and treatment were comparable for both routes. DSM265 given 3 or 7 days before CHMI was safe and well tolerated but sterilely protected only one third of participants.


Assuntos
Antimaláricos/administração & dosagem , Quimioprevenção/métodos , Malária Falciparum/prevenção & controle , Pirimidinas/administração & dosagem , Triazóis/administração & dosagem , Adolescente , Adulto , Animais , Antimaláricos/efeitos adversos , Antimaláricos/farmacocinética , Método Duplo-Cego , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Parasitemia/prevenção & controle , Placebos/administração & dosagem , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Reação em Cadeia da Polimerase em Tempo Real , Resultado do Tratamento , Triazóis/efeitos adversos , Triazóis/farmacocinética , Adulto Jovem
12.
Depress Anxiety ; 34(9): 836-844, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28499066

RESUMO

BACKGROUND: Western societies often overemphasize the pursuit of happiness, and regard negative feelings such as sadness or anxiety as maladaptive and unwanted. Despite this emphasis on happiness, the amount of people suffering from depressive complaints is remarkably high. To explain this apparent paradox, we examined whether experiencing social pressure not to feel sad or anxious could in fact contribute to depressive symptoms. METHODS: A sample of individuals (n = 112) with elevated depression scores (Patient Health Questionnaire [PHQ-9] ≥ 10) took part in an online daily diary study in which they rated their depressive symptoms and perceived social pressure not to feel depressed or anxious for 30 consecutive days. Using multilevel VAR models, we investigated the temporal relation between this perceived social pressure and depressive symptoms to determine directionality. RESULTS: Primary analyses consistently indicated that experiencing social pressure predicts increases in both overall severity scores and most individual symptoms of depression, but not vice versa. A set of secondary analyses, in which we adopted a network perspective on depression, confirmed these findings. Using this approach, centrality analysis revealed that perceived social pressure not to feel negative plays an instigating role in depression, reflected by the high out- and low instrength centrality of this pressure in the various depression networks. CONCLUSIONS: Together, these findings indicate how perceived societal norms may contribute to depression, hinting at a possible malignant consequence of society's denouncement of negative emotions. Clinical implications are discussed.


Assuntos
Transtorno Depressivo Maior , Emoções , Percepção Social , Adulto , Idoso , Transtorno Depressivo Maior/etnologia , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Mol Ther ; 23(5): 857-865, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25648263

RESUMO

Eliminating malaria parasites during the asymptomatic but obligate liver stages (LSs) of infection would stop disease and subsequent transmission. Unfortunately, only a single licensed drug that targets all LSs, Primaquine, is available. Targeting host proteins might significantly expand the repertoire of prophylactic drugs against malaria. Here, we demonstrate that both Bcl-2 inhibitors and P53 agonists dramatically reduce LS burden in a mouse malaria model in vitro and in vivo by altering the activity of key hepatocyte factors on which the parasite relies. Bcl-2 inhibitors act primarily by inducing apoptosis in infected hepatocytes, whereas P53 agonists eliminate parasites in an apoptosis-independent fashion. In combination, Bcl-2 inhibitors and P53 agonists act synergistically to delay, and in some cases completely prevent, the onset of blood stage disease. Both families of drugs are highly effective at doses that do not cause substantial hepatocyte cell death in vitro or liver damage in vivo. P53 agonists and Bcl-2 inhibitors were also effective when administered to humanized mice infected with Plasmodium falciparum. Our data demonstrate that host-based prophylaxis could be developed into an effective intervention strategy that eliminates LS parasites before the onset of clinical disease and thus opens a new avenue to prevent malaria.


Assuntos
Antimaláricos/farmacologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Fígado/parasitologia , Malária/parasitologia , Plasmodium/efeitos dos fármacos , Plasmodium/fisiologia , Profilaxia Pós-Exposição , Animais , Antimaláricos/administração & dosagem , Linhagem Celular , Modelos Animais de Doenças , Feminino , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Indóis , Malária/tratamento farmacológico , Malária/metabolismo , Malária/prevenção & controle , Malária Falciparum/tratamento farmacológico , Malária Falciparum/metabolismo , Malária Falciparum/parasitologia , Malária Falciparum/prevenção & controle , Camundongos , Camundongos Transgênicos , Carga Parasitária , Piperazinas/administração & dosagem , Piperazinas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirróis/administração & dosagem , Pirróis/farmacologia , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismo
14.
J Clin Microbiol ; 53(4): 1355-7, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25609724

RESUMO

A patient in Washington State harbored a fish tapeworm most likely acquired from eating raw salmon. Diphyllobothrium nihonkaiense was identified by cox1 sequence analysis. Although this is the first documented human D. nihonkaiense infection in the United States, the parasite may have been present earlier but misidentified as Diphyllobothrium latum.


Assuntos
Difilobotríase/parasitologia , Diphyllobothrium/isolamento & purificação , Animais , Anti-Helmínticos/uso terapêutico , Difilobotríase/tratamento farmacológico , Diphyllobothrium/enzimologia , Diphyllobothrium/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Parasitologia de Alimentos , Humanos , Filogenia , Praziquantel/uso terapêutico , Adulto Jovem
15.
Proc Natl Acad Sci U S A ; 110(15): 6055-60, 2013 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-23530242

RESUMO

Development of an antimalarial subunit vaccine inducing protective cytotoxic T lymphocyte (CTL)-mediated immunity could pave the way for malaria eradication. Experimental immunization with sporozoites induces this type of protective response, but the extremely large number of proteins expressed by Plasmodium parasites has so far prohibited the identification of sufficient discrete T-cell antigens to develop subunit vaccines that produce sterile immunity. Here, using mice singly immunized with Plasmodium yoelii sporozoites and high-throughput screening, we identified a unique CTL response against the parasite ribosomal L3 protein. Unlike CTL responses to the circumsporozoite protein (CSP), the population of L3-specific CTLs was not expanded by multiple sporozoite immunizations. CSP is abundant in the sporozoite itself, whereas L3 expression does not increase until the liver stage. The response induced by a single immunization with sporozoites reduces the parasite load in the liver so greatly during subsequent immunizations that L3-specific responses are only generated during the primary exposure. Functional L3-specific CTLs can, however, be expanded by heterologous prime-boost regimens. Thus, although repeat sporozoite immunization expands responses to preformed antigens like CSP that are present in the sporozoite itself, this immunization strategy may not expand CTLs targeting parasite proteins that are synthesized later. Heterologous strategies may be needed to increase CTL responses across the entire spectrum of Plasmodium liver-stage proteins.


Assuntos
Plasmodium yoelii/imunologia , Proteínas de Protozoários/imunologia , Esporozoítos/imunologia , Linfócitos T/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Separação Celular , Ensaio de Imunoadsorção Enzimática , Epitopos/imunologia , Imunização , Imunofenotipagem , Interferon gama/metabolismo , Vacinas Antimaláricas/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Peptídeos/imunologia , Proteínas de Protozoários/metabolismo , Análise de Sequência de DNA , Linfócitos T/parasitologia
16.
J Mol Diagn ; 13(3): 359-62, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21458380

RESUMO

The differential diagnosis of diarrhea in immunocompromised patients encompasses many intestinal parasites including the coccidian Cystoisospora belli. Gastrointestinal infection with C. belli leads to cystoisosporiasis with diarrhea and, depending on host immune status, can cause extraintestinal disease. C. belli is usually diagnosed by examination of stool or intestinal biopsy specimens; however, the organism may be undetected using these test methods. Thus, more sensitive molecular tools for detection of pathogenic parasites are desirable. Herein is described a patient with AIDS who had persistent diarrhea of unknown cause. Microscopic examinations of stool and ileal biopsy specimens were initially unremarkable for any specific pathogen. Screening of DNA extracted from biopsy material using extended-range PCR primers recognizing conserved DNA sequences found in many fungi and parasites revealed infection with C. belli, which was confirmed at repeat histologic analysis. Extended-range PCR screening was used because the differential diagnosis was broad and other tools were not applied, yet this molecular approach led to the appropriate diagnosis and treatment of the condition. Thus, this approach offers a promising test for diagnosis of parasitic diseases that elude diagnosis using conventional methods.


Assuntos
Isosporíase/diagnóstico , Reação em Cadeia da Polimerase , Adulto , DNA Espaçador Ribossômico/genética , Infecções por HIV/complicações , Humanos , Hospedeiro Imunocomprometido/imunologia , Isospora/genética , Isosporíase/complicações , Isosporíase/patologia , Masculino , RNA Ribossômico/genética
17.
PLoS Med ; 3(12): e528, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17194200

RESUMO

BACKGROUND: Malaria remains a serious health problem because resistance develops to all currently used drugs when their parasite targets mutate. Novel antimalarial drug targets are urgently needed to reduce global morbidity and mortality. Our prior results suggested that inhibiting erythrocyte Gs signaling blocked invasion by the human malaria parasite Plasmodium falciparum. METHODS AND FINDINGS: We investigated the erythrocyte guanine nucleotide regulatory protein Gs as a novel antimalarial target. Erythrocyte "ghosts" loaded with a Gs peptide designed to block Gs interaction with its receptors, were blocked in beta-adrenergic agonist-induced signaling. This finding directly demonstrates that erythrocyte Gs is functional and that propranolol, an antagonist of G protein-coupled beta-adrenergic receptors, dampens Gs activity in erythrocytes. We subsequently used the ghost system to directly link inhibition of host Gs to parasite entry. In addition, we discovered that ghosts loaded with the peptide were inhibited in intracellular parasite maturation. Propranolol also inhibited blood-stage parasite growth, as did other beta2-antagonists. beta-blocker growth inhibition appeared to be due to delay in the terminal schizont stage. When used in combination with existing antimalarials in cell culture, propranolol reduced the 50% and 90% inhibitory concentrations for existing drugs against P. falciparum by 5- to 10-fold and was also effective in reducing drug dose in animal models of infection. CONCLUSIONS: Together these data establish that, in addition to invasion, erythrocyte G protein signaling is needed for intracellular parasite proliferation and thus may present a novel antimalarial target. The results provide proof of the concept that erythrocyte Gs antagonism offers a novel strategy to fight infection and that it has potential to be used to develop combination therapies with existing antimalarials.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Antimaláricos/farmacologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/fisiologia , Proteínas de Ligação ao GTP/efeitos dos fármacos , Propranolol/farmacologia , Animais , Antimaláricos/uso terapêutico , Antiprotozoários/uso terapêutico , Artemisininas/uso terapêutico , Quimioterapia Combinada , Membrana Eritrocítica/química , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/parasitologia , Membrana Eritrocítica/fisiologia , Eritrócitos/química , Eritrócitos/parasitologia , Humanos , Malária/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Nucleotidases/análise , Plasmodium falciparum/efeitos dos fármacos , Propranolol/uso terapêutico , Sesquiterpenos/uso terapêutico , Transdução de Sinais/fisiologia , Trofozoítos/efeitos dos fármacos
18.
Blood ; 103(5): 1920-8, 2004 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-14592818

RESUMO

Infection of human erythrocytes by the apicomplexan malaria parasite Plasmodium falciparum results in endovacuolar uptake of 4 host proteins that reside in erythrocyte detergent-resistant membranes (DRMs). Whether this vacuolar transport reflects selective uptake of host DRM proteins remains unknown. A further complication is that DRMs of vastly different protein and cholesterol contents have been isolated from erythrocytes. Here we show that isolated DRMs containing the highest cholesterol-to-protein ratio have low protein mass. Liquid chromatography, mass spectrometry, and antibody-based studies reveal that the major DRM proteins are band 3, flotillin-1 and -2, peroxiredoxin-2, and stomatin. Band 3 and stomatin, which reflect the bulk mass of erythrocyte DRM proteins, and all tested non-DRM proteins are excluded from the vacuolar parasite. In contrast, flotillin-1 and -2 and 8 minor DRM proteins are recruited to the vacuole. These data suggest that DRM association is necessary but not sufficient for vacuolar recruitment and there is active, vacuolar uptake of a subset of host DRM proteins. Finally, the 10 internalized DRM proteins show varied lipid and peptidic anchors indicating that, contrary to the prevailing model of apicomplexan vacuole formation, DRM association, rather than lipid anchors, provides the preferred criteria for protein recruitment to the malarial vacuole.


Assuntos
Detergentes/farmacologia , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/parasitologia , Malária/sangue , Malária/patologia , Animais , Proteínas Sanguíneas , Western Blotting , Colesterol/metabolismo , Cromatografia Líquida , Citoplasma/metabolismo , Eritrócitos/metabolismo , Humanos , Immunoblotting , Lipídeos/química , Espectrometria de Massas , Microdomínios da Membrana , Proteínas de Membrana/sangue , Microscopia de Fluorescência , Modelos Biológicos , Peptídeos/química , Peroxidases/sangue , Peroxirredoxinas , Plasmodium falciparum/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
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